In the businesses with the IT, each business worker treats many classified documents where customer information or the latest technical information is described, in which there are serious casualties when these classified documents are brought outside the company (or outside the organization in the range of security management, hereinafter simply referred to as outside the company). Thus, to prevent the classified document from flowing outside the company, there is a demand for a technique for monitoring a file operation. For example, to specify a range of classified information when the classified document flows out, there is a demand for a mechanism for visualizing a file history such as “which file is a source?” or “how the file is changed?”.
Also, a method for illustrating the relationship between file move and copy and copy & paste via a clipboard is disclosed (e.g., refer to patent document 1 and patent document 3). In the patent documents 1 and 3, there is proposed a mechanism for visualizing the relationship between files by recording from which item to which item the copy & paste is made inside the file and how the content is changed.
Also, in patent document 2, it is disclosed that if a development method for copying and modifying the similar process in the program development is employed, a system manages a copy such that when a bug is found in a copied range including an original program, a warning is automatically issued to a user of the copied range.